Cell handover in a radio cellular system

ABSTRACT

When user equipment (UE) is to be handed over, the network and/or the UE determines a best beam for the UE&#39;s interactions with the target cell before the handover is completed. One or more additional next best beams may also be determined. The network (e.g., the target cell) allocates one or more uplink (UL) grants that corresponds to the best beam. Via a current cell, the UE receives the one or more UL grants from the network pertaining to communications between the UE and the target cell. The UE determines whether any beams of the one or more UL grants satisfy beam criteria. The beam criteria may include 1) an allocated beam being the current best beam or 2) an allocated beam being within a strength threshold of the current best beam. If the criteria is not satisfied, the UE initiates another handover type (e.g., a RACH-based handover).

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.16/800,887, entitled “CELL HANDOVER IN A RADIO CELLULAR SYSTEM,” filedFeb. 25, 2020, which claims priority from and the benefit of U.S.Provisional Application Ser. No. 62/888,073, entitled “CELL HANDOVER INA RADIO CELLULAR SYSTEM,” filed Aug. 16, 2019, each of which is herebyincorporated by reference in its entirety for all purposes.

BACKGROUND

The present disclosure relates generally to wireless communicationsystems and, more specifically, to systems and methods for cell handoverin new radio (NR) system.

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentdisclosure. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

In cellular communication networks, each basestation of a cellularnetwork covers a specific area or cell. When a mobile device movesbetween cells, communications between the mobile device and the cellularnetwork is handed over from a current cell to a target cell. The changeof cells may be attributed to physical movement of the mobile device orother reasons (e.g., the previous cell becomes unavailable/has lowerperformance and/or is overly congested). The handover may causetemporary interruption of communication between the mobile device andthe cellular network.

SUMMARY

A summary of certain embodiments disclosed herein is set forth below. Itshould be understood that these aspects are presented merely to providethe reader with a brief summary of these certain embodiments and thatthese aspects are not intended to limit the scope of this disclosure.Indeed, this disclosure may encompass a variety of aspects that may notbe set forth below.

In an embodiment, an electronic device may include a network interfacethat may interface with a cellular network, a memory storinginstructions, and a processor that may execute the instructions. Whenthe instructions are executed, the executed instructions may cause theprocessor to receive, from user equipment, an indication that the userequipment is to be handed over from a current cell to a target cell andreceive, from the user equipment, a measurement report associated withthe target cell to which the user equipment is to be handed over, themeasurement report may include a measurement of a set of beams of thetarget cell. The executed instructions may cause the processor todetermine a beam of the set of beams of the target cell of the cellularnetwork and send, based on the measurement report, an uplink grantcorresponding to the beam to the user equipment, wherein the uplinkgrant is sent as part of a handover from a current cell to a target cellof a cellular network,

In another embodiment, a method may include receiving, at a target cellbase station, an indication that user equipment is to be handed overfrom a current cell to a target cell of a cellular network, receiving,from a current cell base station and at the target cell base station, ameasurement report associated with the target cell to which the userequipment is to be handed over, the measurement report may include ameasurement of a set of beams of the target cell. The method may includedetermining a best beam of the set of beams for communications betweenthe user equipment and the target cell, and allocating a set of uplinkgrants, wherein the set of uplink grants corresponds to the best beamand one or more next best beams, and sending the set of uplink grants tobe sent to the user equipment via the current cell.

In yet another embodiment, a tangible, non-transitory, andcomputer-readable medium having stored thereon instructions, that whenexecuted, may cause one or more processors to receive an indication thatuser equipment is to be handed over from a current cell to a target cellof a cellular network. The executed instructions may cause the one ormore processors to, before completing a handover, determine a best beamfor communications between the user equipment and the target cell,allocate a set of uplink grants, wherein the uplink grants correspond tothe best beam and one or more next best beams, and cause the set ofuplink grants to be sent to the user equipment via the current cell.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of this disclosure may be better understood upon readingthe following detailed description and upon reference to the drawings inwhich:

FIG. 1 is a block diagram of an electronic device that includes anantenna, in accordance with an embodiment of the present disclosure;

FIG. 2 is a perspective view of a notebook computer representing anembodiment of the electronic device of FIG. 1;

FIG. 3 is a front view of a hand-held device representing anotherembodiment of the electronic device of FIG. 1;

FIG. 4 is a front view of another hand-held device representing anotherembodiment of the electronic device of FIG. 1;

FIG. 5 is a front view of a desktop computer representing anotherembodiment of the electronic device of FIG. 1;

FIG. 6 is a front view and side view of a wearable electronic devicerepresenting another embodiment of the electronic device of FIG. 1;

FIG. 7 is a diagram of a cellular network that connects to theelectronic device of FIG. 1, in accordance with embodiments of thepresent disclosure;

FIG. 8 is a diagram of a cellular network that connects to theelectronic device of FIG. 1 using a beam management framework, inaccordance with embodiments of the present disclosure;

FIG. 9 is a flow diagram of a process of the cellular network of FIG. 8allocating one or more uplink (UL) grants, in accordance withembodiments of the present disclosure;

FIG. 10 is a flow diagram of a process of the electronic deviceperforming a cell handover in the cellular network of FIG. 8 when thecellular network allocates one UL grant, in accordance with embodimentsof the present disclosure; and

FIG. 11 is a flow diagram of a process of the electronic deviceperforming a cell handover in the cellular network of FIG. 8 when thecellular network allocates multiple UL grants, in accordance withembodiments of the present disclosure.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments will be described below. In an effortto provide a concise description of these embodiments, not all featuresof an actual implementation are described in the specification. Itshould be appreciated that in the development of any such actualimplementation, as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

As previously discussed, handovers of a mobile device between cells of acellular network may result an interruption of data communicationbetween the cellular network and the mobile device. To perform thehandover, a random access channel (RACH) may be used by the cellularnetwork. The RACH is a shared channel used by the mobile device toset-up calls and to establish how the communications are to be performedwith the new cell in a handover. To reduce the interruption time, thehandovers may utilize a make-before-break procedure (MBB) thatestablishes a new connection for the mobile device to the target cellbefore a connection to the current cell is broken. With the use ofsynchronized base stations, a RACH-less handover may be used to decreasetarget cell access time to further reduce the period of interruption dueto the handover.

As discussed below, the use of a RACH-less handover may create issues in5G new radio (NR) that utilizes beam management. When using RACH incellular networks that utilize beam management, the RACH phase may beused to establish beams used in communications using the cellularnetworks having beam management frameworks. However, when the mobiledevice skips the RACH phase, the mobile device is pre-allocated anuplink (UL) grant in the target cell to which the mobile device is beinghanded over. The UL grant is used to enable a data transfer between themobile device and the target cell. In some embodiments, the UL grant hasa set delay period (e.g., 4 ms) between receipt of the UL grant andbeginning the data transfer to the target cell. Ideally, the beamcorresponding to the UL grant in NR systems is the best beam for theconnection between the basestation and the mobile device. However, eventhough the network and/or the mobile device may determine the best beam,the beam used for the mobile device may not be the best beam for thecommunications between the basestation and the mobile device after thehandover. For example, between the allocation of the UL grant to themobile device and the establishment of the connection between the mobiledevice and the basestation of the target cell, a current best may havechanged and may be different than the pre-allocated beam. Without theRACH phase, the mobile device is unable to indicate which beam is thebest beam to the basestation of the target cell. Without thisindication, the target cell's basestation may continue using theoriginally allocated beam even though the allocated beam is not the bestbeam.

With the foregoing in mind, there are many suitable electronic devicesthat may benefit from the embodiments for cellular handovers describedherein. Turning first to FIG. 1, an electronic device 10 according to anembodiment of the present disclosure may include, among other things,one or more processor(s) 12, memory 14, nonvolatile storage 16, adisplay 18, antenna(s) 20, input structures 22, an input/output (I/O)interface 24, and a network interface 25. The various functional blocksshown in FIG. 1 may include hardware elements (including circuitry),software elements (including computer code stored on a computer-readablemedium) or a combination of both hardware and software elements. Itshould be noted that FIG. 1 is merely one example of a particularimplementation and is intended to illustrate the types of componentsthat may be present in electronic device 10.

By way of example, the electronic device 10 may represent a blockdiagram of the notebook computer depicted in FIG. 2, the handheld devicedepicted in FIG. 3, the handheld device depicted in FIG. 4, the desktopcomputer depicted in FIG. 5, the wearable electronic device depicted inFIG. 6, or similar devices. It should be noted that the processor(s) 12and other related items in FIG. 1 may be generally referred to herein as“data processing circuitry.” Such data processing circuitry may beembodied wholly or in part as software, firmware, hardware, or anycombination thereof. Furthermore, the data processing circuitry may be asingle contained processing module or may be incorporated wholly orpartially within any of the other elements within the electronic device10.

In the electronic device 10 of FIG. 1, the processor(s) 12 may beoperably coupled with the memory 14 and the nonvolatile storage 16 toperform various algorithms. Such programs or instructions executed bythe processor(s) 12 may be stored in any suitable article of manufacturethat includes one or more tangible, computer-readable media at leastcollectively storing the instructions or routines, such as the memory 14and the nonvolatile storage 16. The memory 14 and the nonvolatilestorage 16 may include any suitable articles of manufacture for storingdata and executable instructions, such as random-access memory,read-only memory, rewritable flash memory, hard drives, and opticaldiscs. In addition, programs (e.g., an operating system) encoded on sucha computer program product may also include instructions that may beexecuted by the processor(s) 12 to enable the electronic device 10 toprovide various functionalities.

In certain embodiments, the display 18 may be a liquid crystal display(LCD), which may allow users to view images generated on the electronicdevice 10. In some embodiments, the display 18 may include a touchscreen, which may allow users to interact with a user interface of theelectronic device 10. Furthermore, it should be appreciated that, insome embodiments, the display 18 may include one or more organic lightemitting diode (OLED) displays, or some combination of LCD panels andOLED panels.

The input structures 22 of the electronic device 10 may enable a user tointeract with the electronic device 10 (e.g., pressing a button toincrease or decrease a volume level). The I/O interface 24 may enableelectronic device 10 to interface with various other electronic devices,as may the network interface 25. The network interface 25 may include,for example, one or more interfaces for a personal area network (PAN),such as a Bluetooth network, for a local area network (LAN) or wirelesslocal area network (WLAN), such as an 802.11x Wi-Fi network, and/or fora wide area network (WAN), such as a 3rd generation (3G) cellularnetwork, universal mobile telecommunication system (UMTS), 4thgeneration (4G) cellular network, long term evolution (LTE) cellularnetwork, or long term evolution license assisted access (LTE-LAA)cellular network, 5th generation (5G) cellular network, and/or 5G NewRadio (5G NR) cellular network. The network interface 25 may alsoinclude one or more interfaces for, for example, broadband fixedwireless access networks (WiMAX), mobile broadband Wireless networks(mobile WiMAX), asynchronous digital subscriber lines (e.g., ADSL,VDSL), digital video broadcasting-terrestrial (DVB-T) and its extensionDVB Handheld (DVB-H), ultra-Wideband (UWB), alternating current (AC)power lines, and so forth. For example, network interfaces 25 may becapable of joining multiple networks, and may employ one or moreantennas 20 to that end.

As further illustrated, the electronic device 10 may include a powersource 29. The power source 29 may include any suitable source of power,such as a rechargeable lithium polymer (Li-poly) battery and/or analternating current (AC) power converter.

In certain embodiments, the electronic device 10 may take the form of acomputer, a portable electronic device, a wearable electronic device, orother type of electronic device. Such computers may include computersthat are generally portable (such as laptop, notebook, and tabletcomputers) as well as computers that are generally used in one place(such as conventional desktop computers, workstations, and/or servers).In certain embodiments, the electronic device 10 in the form of acomputer may be a model of a MACBOOK®, MACBOOK® PRO, MACBOOK AIR®,IMAC®, MAC® MINI, OR MAC PRO® available from Apple Inc. By way ofexample, the electronic device 10, taking the form of a notebookcomputer 10A, is illustrated in FIG. 2 in accordance with one embodimentof the present disclosure. The depicted computer 10A may include ahousing or enclosure 36, a display 18, input structures 22, and ports ofan I/O interface 24. In one embodiment, the input structures 22 (such asa keyboard and/or touchpad) may be used to interact with the computer10A, such as to start, control, or operate a GUI or applications runningon computer 10A. For example, a keyboard and/or touchpad may allow auser to navigate a user interface or application interface displayed ondisplay 18.

FIG. 3 depicts a front view of a handheld device 10B, which representsone embodiment of the electronic device 10. The handheld device 10B mayrepresent, for example, a portable phone, a media player, a personaldata organizer, a handheld game platform, or any combination of suchdevices. By way of example, the handheld device 10B may be a model of anIPOD® OR IPHONE® available from Apple Inc. of Cupertino, Calif. Thehandheld device 10B may include an enclosure 36 to protect interiorcomponents from physical damage and to shield them from electromagneticinterference. The enclosure 36 may surround the display 18. The I/Ointerfaces 24 may open through the enclosure 36 and may include, forexample, an I/O port for a hardwired connection for charging and/orcontent manipulation using a standard connector and protocol, such asthe Lightning connector provided by Apple Inc., a universal serial bus(USB), or other similar connector and protocol.

User input structures 22, in combination with the display 18, may allowa user to control the handheld device 10B. For example, the inputstructures 22 may activate or deactivate the handheld device 10B,navigate user interface to a home screen, a user-configurableapplication screen, and/or activate a voice-recognition feature of thehandheld device 10B. Other input structures 22 may provide volumecontrol, or may toggle between vibrate and ring modes. The inputstructures 22 may also include a microphone may obtain a user's voicefor various voice-related features, and a speaker may enable audioplayback and/or certain phone capabilities. The input structures 22 mayalso include a headphone input may provide a connection to externalspeakers and/or headphones.

FIG. 4 depicts a front view of another handheld device 10C, whichrepresents another embodiment of the electronic device 10. The handhelddevice 10C may represent, for example, a tablet computer, or one ofvarious portable computing devices. By way of example, the handhelddevice 10C may be a tablet-sized embodiment of the electronic device 10,which may be, for example, a model of an IPAD® available from Apple Inc.of Cupertino, Calif.

Turning to FIG. 5, a computer 10D may represent another embodiment ofthe electronic device 10 of FIG. 1. The computer 10D may be anycomputer, such as a desktop computer, a server, or a notebook computer,but may also be a standalone media player or video gaming machine. Byway of example, the computer 10D may be an IMAC®, a MACBOOK®, or othersimilar device by Apple Inc. It should be noted that the computer 10Dmay also represent a personal computer (PC) by another manufacturer. Asimilar enclosure 36 may be provided to protect and enclose internalcomponents of the computer 10D such as the display 18. In certainembodiments, a user of the computer 10D may interact with the computer10D using various peripheral input structures 22, such as the keyboard22A or mouse 22B, which may connect to the computer 10D.

Similarly, FIG. 6 depicts a wearable electronic device 10E representinganother embodiment of the electronic device 10 of FIG. 1 that may beconfigured to operate using the techniques described herein. By way ofexample, the wearable electronic device 10E, which may include awristband 43, may be an APPLE WATCH® by Apple Inc. However, in otherembodiments, the wearable electronic device 10E may include any wearableelectronic device such as, for example, a wearable exercise monitoringdevice (e.g., pedometer, accelerometer, heart rate monitor), or otherdevice by another manufacturer. The display 18 of the wearableelectronic device 10E may include a touch screen display 18 (e.g., LCD,OLED display, active-matrix organic light emitting diode (AMOLED)display, and so forth), as well as input structures 22, which may allowusers to interact with a user interface of the wearable electronicdevice 10E.

With the foregoing in mind, FIG. 7 illustrates an example of cellularcommunications network 100 to which the electronic device 10 connects.Although the electronic device 10 is illustrated as a cellular phone,the cellular communications network 100 may connect to any electronicdevice that has a corresponding radio, such as an LTE or 5G radio, aspart of its network interface 25 and antenna 20. The cellularcommunications network 100 includes a basestation 102 that is used toimplement at least a portion of a cell 104. Similarly, the cellularcommunications network 100 includes a basestation 106 that is used toimplement at least a portion of a cell 108. The basestations 102 and 106may include and/or utilize a computing device (e.g., another iterationof the electronic device 10) to perform computations and/or implementprogram code to perform specific tasks.

At some point, the connection to the basestation 102 becomes lessdesirable than a connection to the basestation 106. This change may bedue to the electronic device 10 exiting the cell 104 or the basestation102 otherwise becoming congested/unavailable to the electronic device10. At this point, the electronic device 10 is handed over from the cell103 to the cell 108. In some embodiments, the handover may utilize aRandom Access Channel (RACH) of the basestation 106 to setup theconnection between the basestation 106 and the electronic device 10.However, due to the break of the connection between the electronicdevice 10 and the basestation 102 and establishment of the connectionbetween the electronic device 10 and the basestation 106, the electronicdevice 10 may undergo a temporary interruption of service due to thehandover. To reduce this interruption, a make-before-break (MBB)handover may be made. During an MBB handover, the connection between thebasestation 106 and the electronic device 10 may be made before theconnection between the basestation 102 and the electronic device 10 maybe broken. Furthermore, due to availability of synchronization betweenthe basestations 102 and 106, the setup of the connection between thebasestation 106 and the electronic device 10 may be performed withoutusing the RACH in a RACH-less handover. A RACH-less handover furtherreduces the handover delay and it associated interruption time due tothe handover. A RACH-less mechanism (as applied to LTE) includes apre-allocation of an uplink (UL) grant in the cell 108 since the RACHphase is skipped in the handover. A possible method of performing thepre-allocation includes allocating a fixed grant that are sent to theelectronic device 10 via the cell 104 before the handover. Analternative method of performing the pre-allocation may include the cell108 continuously performing the UL grant by using a user equipment (UE)cell-radio network temporary identifier (C-RNTI) that is typically usedto transmit to a specific UE (e.g., the electronic device 10) after RACHwhen RACH is used.

For LTE and 5G NR Frequency Range 1 (FR1) less than 7 GHz, thepreviously RACH-less handover mechanism may be suitable for handovers.However, for 5G NR Frequency Range 2 (FR2) having a frequency greaterthan 7 GHz (e.g., 7-24 GHz) that utilize beam management frameworks, aRACH-less handover mechanism should account for beam management.

FIG. 8 illustrates a cellular communications network 110 that utilizes5G NR FR2. As illustrated, a basestation 112 uses beams 114 and 116 toexchange information with UEs (e.g., electronic device 10) in a cell118. Similarly, a basestation 120 may use beams 122, 124, and 126 toexchange information with UEs in a cell 128. Although two beams (beams114 and 116) are illustrated in the cell 118 and three beams (e.g.,beams 122, 124, and 126) are illustrated in the cell 128, any suitablenumber of beams may be deployed within the cells 118 and 128. During aRACH-based handover, the electronic device 10 may instruct thebasestation 120 which beam should be used in transmitting data to thebasestation 120. For example, the basestation 120 may determine thatbeam 122 is the best beam for communications with the electronic device10. However, the best beam may change before and/or during the RACHphase. Accordingly, the electronic device 10 may instruct thebasestation 120 that a different beam, beam 124, is now the best beamfor communications between the basestation 120 and the electronic device10 since the best beam has changed.

Consequently, when a RACH-less handover occurs, the RACH phase isomitted, and the electronic device 10 is unable to directly instruct thebasestation 120 as to which beam is the best. For example, in aRACH-less handover, the basestation 120 may rely on the beam 122 beingthe best beam from measurement reports (e.g., received from thebasestation 112) even though the beam 124 is currently the best beam forcommunications between the electronic device 10 and the basestation 120.In other words, without a RACH phase the communications between theelectronic device 10 and the basestation 120 may use an inferior beamrather than the best beam thereby possibly reducing efficiency ofcommunications between the electronic device 10 and the basestation 120.

One approach that may be used to account for beam management frameworks(e.g., 5G NR FR2) includes allocating additional UL grants to the UEwhen a handover between cells occurs. For instance, FIG. 9 illustrates amethod 140 that may be implemented for the cell 128 to account for beammanagement. The method 140 may be performed using the basestation 120and/or an associated computing device including a processor and memorysimilar to those discussed in relation to the electronic device 10. Forexample, a computing device may be used to control network actions forthe cell and/or within the cell 128. For instance, in some embodiments,the computing device may be another instance of the computer 10D. Thenetwork (e.g., using the computing device) receives an indication thatuser equipment is to be handed over from the cell 118 to the cell 128(block 142). For instance, the indication may indicate that astrength-of-signal (SoS) for communications between the electronicdevice 10 and the cell 118 has fallen below a threshold. Additionally oralternatively, the indication may indicate that a SoS for communicationwith the cell 128 is likely to exceed another threshold. For instance,this likelihood may be made based on a determined location of theelectronic device 10 in relation to where the basestation 120 islocated. Based on measurement reports, the basestation 112, thebasestation 120, another basestation, the electronic device 10, and/orother processing within the network (e.g., central processing controlcenter) determines a best beam (e.g., strongest beam) for communicationbetween the electronic device 10 and the cell 128 (block 144). In someembodiments, the network may determine the best beam using a measurementreport from the electronic device 10 or may determine the best beam byreceiving an indication of the best beam from the electronic device 10.

The network allocates one or more UL grants for the electronic device 10to communicate with the cell 128 (block 146). For instance, thebasestation 112, the basestation 120, another basestation, and/or otherprocessing within the network (e.g., central processing control center)may be used to allocate the one or more UL grants. Granting the one ormore UL grants may include sending the UL grants to the electronicdevice 10 for communication with the cell 128 by sending the UL grantsvia the cell 118.

The one or more UL grants may be based at least in part on receivedmeasurements from the cell 118 from which the electronic device 10 isbeing handed off. The measurement report may be based on synchronizationsignal block (SSB) or channel state information reference signals(CSI-RS) that are used to estimate channel quality and report channelquality information. These measurement reports for communication betweenthe cell 118 and the electronic device 10 may be used to determine theUL grants. Specifically, the one or more UL grants includes at least thebest beam for communications between the electronic device 10 and thecell 128 based on measurements from the cell 118 that are transmitted tothe electronic device 10 via the cell 118. For example, the network maygrant the electronic device 10 three UL grants that correspond to first,second, and third best beams based on the previous measurement reports.The network may grant the multiple UL grants to the electronic device 10to account for the possibility that the beam designated as the best beamdue to the previous reports may have changed before the handover iscompleted. For instance, the best beam may have changed since themeasurements. In other words, even though the electronic device 10 mayknow some information about the cell 128 before the handover but thesituation may change before the handover is completed. The additionallygranted UL grants makes it more likely that the electronic device 10 isgranted a UL grant that corresponds to the best beam at and/or after thehandover is completed. Some deployments of 5G NR FR2 networks may usemultiple UL grants to ensure best beam fidelity during a handoff whileothers use only a single UL grant to prevent the electronic device 10from consuming too many resources within the cellular network.

The electronic device 10 responds to the number of UL grants accordingto the number of UL grants received. FIG. 10 is a flow diagram of aprocess 150 that may be used by the electronic device 10 in a handoverwhere the electronic device 10 is allocated one UL grant as part of thehandover. The electronic device 10 measures a target cell (block 152).For instance, the electronic device 10 uses the antenna 20 to measureinformation about the cell 128 using SSB and/or CSI-RS. The electronicdevice 10 then sends a measurement report pertaining to the cell 128 viathe cell 118 (block 154). The cell 128 allocates a UL grantcorresponding to a best beam for a handover to the cell 128. Theelectronic device 10 receives the UL grant from the cell 118 (block156). The electronic device 10 then stores the best reported beam. Theelectronic device then performs the handover using the beamcorresponding to the allocated UL grant (block 158). Performing thehandover includes, after handing over, measuring beams for the cell 128.The electronic device then compares the measured beams with the storedallocated beam to determine a current best beam. After the handover, theelectronic device 10 determines whether the allocated beam satisfiescriteria for the handover (block 160). In some embodiments, the criteriamay be that the allocated beam is within a strength threshold (e.g., anumber of decibels) of the current best beam. In some embodiments, thestrength threshold may be determined according to standards, such asstandards set by a radio performance and protocol aspects and radioresource management (RAN4 RRM) group. Additionally or alternatively, thethreshold may be set to 0.0 dBs. In other words, the criteria mayindicate that the allocated beam is to be used only when the allocatedbeam remains the best beam for communications between the electronicdevice 10 and the cell 128. Regardless of the value, the strengththreshold value may be a parameter that is set for the electronic device10 using a signal received by the electronic device 10 from the cellularnetwork. Additionally or alternatively, the strength threshold may bedefined by the electronic device 10.

Based on whether the connection with the cell 128 satisfies thecriteria, the electronic device 10 determines how to proceed withfurther communication with the cell 128. If allocated beam satisfies thecriteria by being the best beam or within a strength threshold of thebest beam, the electronic device 10 continues communication with thetarget cell using the allocated beam that corresponds to the allocatedUL grant (block 162). However, if the allocated beam does not satisfyingthe criteria by being outside a strength threshold of the best beam, theelectronic device 10 initiates a RACH procedure to update the beam usinga RACH handover to allocate the best beam (block 164). For instance, theelectronic device 10 may send a message to the basestation 112 and/orthe basestation 120 to initiate the RACH handover. The RACH handover mayinclude the UE measuring a RACH downlink (DL), transmitting measurementspertaining to the RACH DL to the network, and receiving a new UL grant.After receiving a new UL grant, the electronic device uses the newlyallocated beam to communicate with the cell 128 (block 166).

FIG. 11 is a flow diagram of a process 170 that may be used by theelectronic device 10 in a handover where the electronic device 10 isallocated two or more UL grants as part of the handover. The electronicdevice 10 measures a target cell (block 172). For instance, theelectronic device 10 uses the antenna 20 to measure information aboutthe cell 128 using SSB and/or CSI-RS. The electronic device 10 thensends a measurement report pertaining to beams of the cell 128 via thecell 118 (block 174). The cell 128 allocates two or more UL grantscorresponding to the strongest two or more (e.g., 3) measured beams,including the best beam, for a handover to the cell 128. The electronicdevice 10 receives the UL grants from the cell 118 (block 176). Theelectronic device 10 then stores the best reported beams that areallocated. The electronic device then performs the handover using thebest beam corresponding to the allocated UL grants (block 178).Performing the handover includes, after handing over, measuring beamsfor the cell 128. The electronic device then compares the measured beamswith the stored allocated beams to determine a current best beam. Afterthe handover, the electronic device 10 determines whether any of theallocated beam satisfy criteria for the handover (block 180). In someembodiments, the criteria may be that any of the allocated beams iswithin a strength threshold (e.g., a number of decibels) of the currentbest beam. As previously discussed, the strength threshold may bedetermined according to standards, such as standards set by a radioperformance and protocol aspects and radio resource management (RAN4RRM) group. Additionally or alternatively, the threshold may be set to0.0 dBs. In other words, the criteria may indicate that one of theallocated beams is to be used only when the corresponding allocated beamis the current best beam for communications between the electronicdevice 10 and the cell 128. Regardless of the value, the value of thestrength threshold may be a parameter that is set for the electronicdevice 10 using a signal received by the electronic device 10 from thecellular network. Additionally or alternatively, the strength thresholdmay be defined by the electronic device 10.

Based on whether the one of the allocated beams satisfies the criteria,the electronic device 10 determines how to proceed with furthercommunication with the cell 128. If any of the allocated beams satisfiesthe criteria by being the best beam or within a strength threshold ofthe best beam, the electronic device 10 continues communication with thetarget cell 128 using the best allocated beam that corresponds to theallocated UL grants (block 182). For example, the UL grants maycorrespond to beams 122, 124, and 126. The beam 122 may be the originalmeasured best beam before the handover, while the beam 124 is the bestbeam after handover. Since the best beam is allocated to the electronicdevice 10, the electronic device 10 may switch from using the beam 122to using the beam 124 in communications with the cell 128.

As previously discussed, in situations where a non-zero threshold isutilized, the allocated beams may not be the best beam but may be usedfor communication with the cell 128 as long as the used allocated beamis within the strength threshold of the current best beam. For example,consider that the beams 122, 124, and 126 are allocated for the handoverwith the beam 122 being the best beam and an additional beam (not shown)is determined to be the best beam after handover. If the beams 122 and124 are within the strength threshold of the additional beam, the beams122 and 124 satisfy the criteria. The electronic device 10 then may usethe beam 122 or the beam 124 for communication with the cell 128. If thebeam 122 is now less strong at the electronic device 10 than the beam124, the electronic device 10 may switch to using the beam 124 forcommunication with the cell 128. Otherwise, the electronic device 10 maycontinue to use the beam 122 for communication with the cell 128.

The electronic device 10 may switch between beams as long as thecorresponding UL grants have not expired. In some embodiments, the ULgrants may be prevented from expiring until an event has occurred toenable expiration of the unused UL grants. For example, the event mayinclude a longer delay than a typical expiration during a handoverand/or may include the electronic device 10 being handed over from thecell 128 to another cell. Additionally or alternatively, the event mayinclude the electronic device 10 fully completing the handover and usingone of the beams to initiate data transfer with the cell 128.Additionally or alternatively, the event may include the electronicdevice 10 sending a release signal that indicates that the unusedallocated UL grants are no longer needed. Thus, unless the event hasoccurred, the electronic device 10 is free to change between theallocated beams.

However, if none of the allocated beams satisfies the criteria by beingwithin the strength threshold of the best beam, the electronic device 10initiates a RACH procedure to update the beam using a RACH handover toallocate the best beam (block 184). For instance, the electronic device10 may send a message to the basestation 112 and/or the basestation 120to initiate the RACH handover. The RACH handover may include the UEmeasuring a RACH downlink (DL), transmitting measurements pertaining tothe RACH DL to the network, and receiving a new UL grant. Afterreceiving a new UL grant, the electronic device uses the newly allocatedbeam to communicate with the cell 128 (block 186).

The specific embodiments described above have been shown by way ofexample, and it should be understood that these embodiments may besusceptible to various modifications and alternative forms. For example,the processes may be applied for embodiments having different numbersand/or locations for antennas, different groupings, and/or differentnetwork arrangements. Moreover, it should be further understood thatforegoing processes may be performed by suitable computing devices(e.g., the electronic device 10) using tangible, non-transitory, andcomputer-readable medium (e.g., the memory 14 and/or the storage 16)storing instructions that when performed by one or more processors(e.g., processor(s) 12) are configured to cause the one or moreprocessors to perform the foregoing processes. Furthermore, it should befurther understood that the claims are not intended to be limited to theparticular forms disclosed, but rather to cover all modifications,equivalents, and alternatives falling within the spirit and scope ofthis disclosure. For example, various embodiments of the processes mayinclude combinations of blocks, rearrangement of blocks, and/oradditional blocks that includes subject matter that is within the spiritand scope of this disclosure.

The techniques presented and claimed herein are referenced and appliedto material objects and concrete examples of a practical nature thatdemonstrably improve the present technical field and, as such, are notabstract, intangible or purely theoretical. Further, if any claimsappended to the end of this specification contain one or more elementsdesignated as “means for [perform]ing [a function] . . . ” or “step for[perform]ing [a function] . . . ”, it is intended that such elements areto be interpreted under 35 U.S.C. 112(f). However, for any claimscontaining elements designated in any other manner, it is intended thatsuch elements are not to be interpreted under 35 U.S.C. 112(f).

What is claimed is:
 1. An electronic device, comprising: a networkinterface configured to interface with a cellular network; a memorystoring instructions; and a processor configured to execute theinstructions, wherein, when the instructions are executed, areconfigured to cause the processor to receive, from user equipment, anindication that the user equipment is to be handed over from a currentcell to a target cell, receive, from the user equipment, a measurementreport associated with the target cell to which the user equipment is tobe handed over, the measurement report comprising a measurement of aplurality of beams of the target cell, determine a beam of the pluralityof beams of the target cell of the cellular network, and send, based onthe measurement report, an uplink (UL) grant corresponding to the beamto the user equipment, wherein the UL grant is sent as part of ahandover from the current cell to the target cell.
 2. The electronicdevice of claim 1, wherein sending the UL grant corresponding to agranted best beam to the user equipment causes the electronic device oranother node of the cellular network to: perform the handover from thecurrent cell to the target cell without using a random access channel(RACH) procedure; and in response to a determination that the grantedbest beam does not satisfy a criteria for a best beam of the targetcell, performing a RACH-based handover to update the target cell bestbeam for communications between the user equipment and the target cell.3. The electronic device of claim 2, wherein, when no new best beamexists, the instructions are configured to cause the electronic deviceto cause the user equipment to continue using the granted best beam tocommunicate with the target cell when the criteria has been satisfied bythe granted best beam, wherein the granted best beam is a current bestbeam.
 4. The electronic device of claim 1, wherein the indicationcomprises a strength-of-signal for communications between the userequipment and the current cell falling beneath a strength-of-signalthreshold.
 5. The electronic device of claim 1, wherein the indicationcomprises a likelihood that a strength-of-signal for communicationsbetween the user equipment and the target cell will exceed astrength-of-signal threshold.
 6. The electronic device of claim 5,wherein the likelihood that the strength-of-signal for communicationsbetween the user equipment and the target cell will exceed thestrength-of-signal threshold is determined based on a location of theuser equipment in relation to the electronic device.
 7. The electronicdevice of claim 1, wherein the measurement report associated with thetarget cell is based on a synchronization signal block used to estimatechannel quality and report channel quality information.
 8. Theelectronic device of claim 1, wherein the measurement report associatedwith the target cell is based on channel state information referencesignals that are used to estimate channel quality and report channelquality information.
 9. The electronic device of claim 1, wherein thecellular network comprises a 5^(th) Generation New Radio FR2 network.10. The electronic device of claim 1, wherein the cellular networkcomprises a frequency range of 7 gigahertz to 24 gigahertz.
 11. Amethod, comprising: receiving, at a target cell base station, anindication that user equipment is to be handed over from a current cellto a target cell of a cellular network; receiving, from a current cellbase station and at the target cell base station, a measurement reportassociated with the target cell to which the user equipment is to behanded over, the measurement report comprising a measurement of aplurality of beams of the target cell; determining a best beam of theplurality of beams for communications between the user equipment and thetarget cell; allocating a plurality of uplink grants, wherein theplurality of uplink grants correspond to the best beam and one or morenext best beams; and sending the plurality of uplink grants to be sentto the user equipment via the current cell.
 12. The method of claim 11,wherein sending the plurality of uplink grants corresponding to agranted best beam to the user equipment causes the target cell basestation, the current cell base station, or another node of the cellularnetwork to: perform a handover to the target cell using the best beamwithout using a random access channel (RACH) procedure; and in responseto a determination that the granted best beam does not satisfy acriteria for a best beam of the target cell, perform a RACH-basedhandover to update the target cell best beam for the communicationsbetween the user equipment and the target cell.
 13. The method of claim12, comprising, after the handover, receiving a measurement of thetarget cell to obtain a post-handover target cell best beam.
 14. Themethod of claim 12, comprising determining the granted best beam basedat least in part on measurements of the current cell.
 15. The method ofclaim 14, wherein the measurements of the current cell are based atleast in part on a synchronization signal block.
 16. The method of claim12, wherein the measurement of the current cell are based at least inpart on a wherein the measurements of the current cell are based atleast in part on channel state information reference signals.
 17. Themethod of claim 11, wherein the cellular network comprises a 5^(th)Generation New Radio FR2 network.
 18. Tangible, non-transitory, andcomputer-readable medium having stored thereon instructions, that whenexecuted, are configured to cause one or more processors to: receive anindication that user equipment (UE) is to be handed over from a currentcell to a target cell of a cellular network; before completing ahandover, determine a best beam for communications between the UE andthe target cell; allocate a plurality of uplink (UL) grants, the ULgrants corresponding to the best beam and one or more next best beams;and cause the plurality of UL grants to be sent to the UE via thecurrent cell.
 19. The tangible, non-transitory, and computer-readablemedium of claim 18, wherein sending the UL grant corresponding to thebest beam to the user equipment causes a base station of the cellularnetwork to: perform the handover from the current cell to the targetcell without using a random access channel (RACH) procedure; and inresponse to a determination that the granted best beam does not satisfya criteria for a best beam of the target cell, initiate a RACH-basedhandover to update the target cell best beam for the communicationsbetween the user equipment and the target cell.
 20. The tangible,non-transitory, and computer-readable medium of claim 19, wherein theinstructions, when executed, are configured to cause the one or moreprocessors to cause a base station of the cellular network to cause theuser equipment to continue using the granted best beam to communicatewith the target cell when the criteria has been satisfied by the grantedbest beam, wherein the granted best beam is a current best beam.